Joints for sheet metal



July so, 1968 E. A. P. HOWARTH 3,394,524

JOINTS FOR SHEET METAL 2 Sheets-Sheet 1 Filed Nov. 1, 1965 FIG. 2.

FIG. 4.

July 30, 1968 I ,E. A. P. HOWARTH JOINTS FOR SHEET METAL 2 Sheets-Sheet 2 Filed Nov. 1, 1965 FIG. 5.

FIG. 7.

United States Patent 3,394,524 JOINTS FOR SHEET METAL Edward A. P. Howarth, 7 Ninian St., Wellington, North Island, New Zealand Filed Nov. 1, 1965, Ser. No. 505,860 Claims priority, application New Zealand, Nov. 5, 1964, 139,893 2 Claims. (Cl. 52-588) ABSTRACT OF THE DISCLOSURE A cladding material or panel structure having complementary male and female inverted channels for jointing means at the longitudinal edges with the female channel having a returned or reversely bent tongue to engage with its free edge in a hook or barb-like engaging action within a groove in the male channel. An upstanding inverted channel integral with and extending upwardly from the main body portion of the panel is located intermediate the male and female channels with the medial channel having its side wall substantially parallel over the initial section and with one side wall stepped out wardly to provide an internal shoulder above the parallel section of the walls. A fastening strip provided with a shaped flange for engagement over the male inverted channel of the previously laid panel is provided at one end of a strap located in the same plane as the body portion and a hook arm extends upwardly perpendicularly from the opposite end of the strap for engagement Within the medial channel. The hook arm includes a tongue arranged to engage over the internal shoulder in the medial channel to constitute a hook-like engagement for preventing withdrawal of the hook arm from the medial channel.

This invention relates to joints for sheet metal and has been devised particularly though not solely for use in joining roofing sheets.

At present there is a considerable demand for roofing sheets which can be adequately fixed to roof rafters and yet which can be provided in continuous lengths over for example the span of a dwelling house from one wall to the opposite wall. There are a considerable number of joints and roofing sheets at present available which endeavor to meet this requirement but is is believe-d that there is a demand for an even better type of joint and roofing sheet incorporating the same which will at least give the public a useful choice.

It is an object of the present invention to provide a panel of cladding material adapted in use to interlock with an adjoining panel of similar cladding material in a manner such that the joint between the adjoining panels is not readily separated by any force substantially normal to the main plane of the cladding material.

It is a further object of the present invention to provide a panel of cladding material adapted in use to interlock with an adjoining panel of similar cladding material with the joint between adjoined panels arranged so that any force tending to separate the panels will cause a more positive engagement between the panels.

One preferred form of the invention and modifications thereof will now be described with reference to the accompanying drawings in which:

FIGURE 1 is a view in perspective of a short length of a panel of cladding material according to the present invention,

FIGURE 2 is a detailed sectional view through a joint formed between two panels according to the present invention,

FIGURE 3 is a view partly in elevation and partly in section showing adjacent panels supported on structural members by a fixing clip,

FIGURE 4 is a view in perspective of one such clip,

FIGURE 5 is a view in section through a portion of a modified panel according to the present invention, showing a completed joint between adjacent panels,

FIGURE 6 is a view in section through a slight modification of the construction shown in FIGURE 5, and

FIGURE 7 is a view in section through a portion of a modified panel according to a yet further form of the invention showing a completed joint between adjacent panels.

In one preferred form of the invention shown in the drawings, a panel 1 is rolled to a shape described in detail herebelow. The panel has particular application to long lengths of cladding material, for example provided to give a sixteen inch coverage. This material is adapted for use both for roof cladding and vertical wall cladding, and may be formed from any suitable metal, for example galvanized steel or a suitable aluminum alloy. However it will be appreciated the sheet may be formed in copper, stainless steel and P.V.C. coated steel in various colors.

The panel 1 thus comprises a substantially flat rectangular body portion 2 which may be formed to any length consistent with available transporting facilities. The width however is normally limited to provide a sixteen inch coverage as above stated. An integral upstanding female inverted channel 3 is provided along one longitudinal edge of the panel 1. A side or wall 4 of the channel 3 extends substantially at right angles to the body portion 2 and is folded over to form a rounded top before continuing on outer side or wall 5 which has the free edge thereof returned upwardly, that is, reversely bent so as to form a hook means provided as a tongue 6 returned to form an internal acute angle and preferably an angle less than sixty degrees between the side 5 and the tongue 6. The hook means is formed above the body portion 2 of the panel 1 and in a preferred construction where the inverted channel is approximately two inches high, the base or lowest portion of the hook is slightly above the mid-point of the channel. Also, in the preferred form, the channel is comparatively narrow, for example in the vicinity of a quarter of an inch.

Along the opposite longitudinal edge of the panel is provided an integral upstanding male member also in the form of an inverted channel 7 with side or wall 8 thereof extending substantially at right angles to the body portion 2 and having the top folded to conform with the inside shape of the female channel 3 and with outer side or wall 9 adapted to return down and in use cooperate against the side 4 of the female channel. The side 9 terminates after it is returned down approximately a third of the distance of the side 4.

A longitudinal groove or depression 10 is formed in the side 8 at approximately the mid-point thereof and in use is adapted to provide an engagement means to engage with the hook means 6 on the female channel. Any suitably shaped depression may be provided in the side 8 to form a shoulder means 11 against which the edge portion of the tongue 6 may abut. Of course, it is desirable to provide a shape which has aesthetic appeal as is illustrated in the accompanying drawings.

The angle of contact between edge 12 of the tongue 6 and the shoulder means 11 in the longitudinal depression 10 should be such that the tongue at least forms a right angle with the shoulder means 11. It is desirable to arrange the joint so that a factor of any force tending to separate the joint will tend to drive the tongue 6 further into the depression 10. In a theoretical model with a smooth surface, the force tending to resist the separation of the joint would act at right angles to the surface of the shoulder means 11. In practice the sheet metal would not provide a theoretically smooth surface and the force would be somewhere between the perpendicular and a force at right angles to the shoulder. Where the angle between the tongue 6 and the tangent to the shoulder means 11 drawn from the point of contact of the edge of the tongue towards the side 8 is ninety degrees or less, any force resisting the separation of the joint would be resolved to give a vector acting to drive the hook inwardly. Thus, in the preferred construction it is preferable that the joint be designed so that the tongue 6 forms an angle of less than ninety degrees between the point of contact and the side 8.

The panel 1 according to the present invention, also includes an integral longitudinal medial channel 13 of similar dimensions to the female channel 3. The medial channel has a shoulder 14 formed by recessing side 15 adjacent the female channel 3 so that the medial channel acts as a female channel to engage with a fastening clip 16 as described herebelow. The fastening clip 16 comprises a strip of metal having a base 16a with a flange 17 adjacent one end having inverted I hook 18 at the end thereof adapted to engage over the male channel of a sheet being fastened. At the opposite end of the base 16 a hook flange is formed comprising an upstanding leg 19 with a hook portion formed by a tongue 20 returned down at an acute angle with the leg 19 and arranged so that the free edge thereof in use engages with the shoulder 14 in the medial channel.

Preferably shallow longitudinal ribs are provided at spaced intervals across the body portion. For example as illustrated in FIGURES 1 and 3, two such shallow longitudinal ribs are provided between the medial channel and both the female and male channels.

To use the cladding panels according to the present invention the required lengths are placed on a structure to be clad which may be either a wall or a roof. The end sheet is provided with flashing in the usual way and it has a male channel associated therewith. This male channel may be fixed with clips if so desired having the inverted J 18 fixed over the male channel. Apertures 16b are provided through the base 16 adjacent both the flange 17 and the flange 19 to attach the clips to a support member 21. A sheet of cladding material may then be placed in position with the female channel clipping over the male channel and the hook means engaging with the hook and the tongue 6 engaging in the depression 10 as above described. The flange 19 will also engage with the medial channel to firmly fix the sheet in position.

Because of the means of clipping, any expansion or contraction in the long lengths of cladding material used will be allowed for, thus largely eliminating expansion, noises and cracks in the metal. Further sheets are similarly positioned after the male inverted channel has again been fixed in position by the fixing clips spaced at suitable intervals.

A particular phenomenon of the present cladding panel is that the joint provided between adjacent sheets acts as a capillary barrier. As is well-known, capillary attraction will cause water to rise above its own level when two surfaces are in contact. This can occur in the side lap of corrugated iron if the pitch of the roof is not great enough and can also occur at the side lap of some flat long-run roofs. The clipping action of the present panel provides a space between the tongue 6 and the upper part of the depression 10 where the surfaces are not in contact and this prevents any capillary attraction.

A further feature of a panel according to the present invention is that the edges are protected from the weather. The free edge of the male channel is clearly protected by the female channel and the free edge of the female channel is protected because of the tongue folded up to engage in the depression 10.

While in the preferred form of the invention, the

narrow rib is provided between the sheets when the male and female channels are engaged, it is envisaged that the invention could be incorporated on panels having wider ribs, for example a panel having wide cooperating male and female channels with or without a plurality of intermediate channels or ribs formed substantially to the same dimensions. A sheet could thus be provided with the spacing provided across the base of the inverted channel approximately equal to the space provided in the depressions between adjacent channels.

In the construction shown in FIGURE 5, a panel 22 has a plurality of ribs 23 having sides 23a thereof inclined at an angle and with base 23b of the troughs between adjacent ribs 23 substantially equal to a flat top 24 provided on the rib. The jointing in this case is similar to that above described with an inverted female channel 25 provided along one longitudinal edge. The edge of free side 26 is turned upwardly to form a hook means in the form of a tongue 27 in a similar manner to that above described. On the opposite side, the first complete rib has a longitudinal groove 27a extending in from the inclined side adjacent the base 23b adapted to receive the tongue 27 also in a similar manner to that previously described. The lap if desired could extend beyond the single jointing rib, that is to include a trough as is illustrated in the drawings. The depth of the ribs would be for example approximately five-eighths of an inch with the base 23b and top 24 also approximately fiveeighths of an inch. It is envisaged that a plurality of ribs, for example two, could be provided interspersed with a flat section thus providing a decorative panel for cladding purposes.

In the alternative form of the invention shown in FIG- URE 6, formation 27b is level with flat base 230. This may give a more pleasing finish where the panels are used for cladding walls.

In a yet further form of the invention shown in FIG- URE 7, a panel 30 is provided having ribs 31 which are substantially symmetrical with troughs 32 formed therebetween again with a flat top provided on the ribs and a flat base in the channel being substantially equal in width. An inverted female channel 33 is formed along one longitudinal edge of the panel and has a hook means provided by a tongue 34 in a similar manner to that previously described. The opposite longitudinal edge has an inverted male channel 35 with a longitudinal groove 36 to be engaged by the tongue 34. r

The use of the above modified constructions is similar to that described with respect to the first construction but the fixing may be modified in accordance with usual fixing techniques.

A further point is that where it is necessary to remove some of the panels according to the present invention an unfastening tool is used to spring the tongue from the depression allowing the sheet to be lifted easily.

The invention is not to be confined to any strict conformity to the showings in the drawings but changes or modifications may be made therein so long as such changes or modifications mark no material departure from the spirit and scope of the appended claims.

What I claim is:

1. A panel of cladding material adapted in use to interlock with an adjoining panel of similar cladding material, said panel comprising a substantially flat rectangular body portion, an integral upstanding female inverted channel along one longitudinal edge of said body portion with the lower free edge of said inverted channel being reversely bent to terminate in a hook means to form a tongue defining an acute angle between said hook means and the remaining portion of the outer side of the female channel, said tongue being located above the plane containing the body portion of said panel, said panel further including an integral upstanding male inverted channel extending along the opposite longitudinal edge of said body portion and adapted in use to engage within said female inverted channel with the two sides of the male and female channels cooperatively engaging one within the other when the channels of adjoining panels are engaged, said male inverted channel having a longitudinally extending depression in the side thereof extending up from the body portion and defining a shoulder, said longitudinal depression being located to receive the tongue of the superimposed female channel of the adjoining panel so that the free edge of the tongue engages with the under surface of said shoulder in a hook-like engagement thereby preventing the ready separation of joined panels, an integral upstanding inverted channel parallel to said male and female channel and intermediately spaced there'between with said medial channel having the side walls substantially parallel over the initial section extending up from the main body portion of the panel and with one side wall stepped outwardly to form an internal shoulder above the initial parallel section of walls and a fastening strip comprising an inverted J-shaped flange shaped to engage over the male inverted channel of a previously laid panel, a fixing strap in the same plane as the body portion of the panel and a hook arm extending up at right angles from the opposite end of said fixing strap to engage within the medial channel, said hook arm having a tongue folded to form an acute angle between the remaining portion of the hook arm and the tongue and with the free edge of the tongue arranged to engage over the internal shoulder in the medial channel to form a hook-like engagement thereby preventing withdrawal of the hook arm from said medial channel.

2. The panel as claimed in claim 1 wherein said female inverted channel is an inverted J with the free end of the J being bent inwardly to form the tongue and said inverted male channel having a section extending substantially at right angles to the main plane of the panel, a longitudinal groove shaped with the upper portion providing the shoulder against which the edge of the tongue of the engaged female channel abuts in use with the tangent drawn through the point of contact between the tongue and the shoulder forming an included angle with the tongue of no more than ninety degrees and a top portion bent reversely to be substantially complementary to the interior of said female inverted channel.

References Cited UNITED STATES PATENTS 2,007,354 7/1935 Vass 52-588 3,031,044 4/1962 Stitt 52-588 3,234,697 2/1966 Toti 52588 FOREIGN PATENTS 1,336,774 1963 France.

257,361 1961 Australia.

FRANK L. ABBOTT, Primary Examiner. P. C. FAW, Assistant Examiner. 

